Of course content creators typically focus on beginners because there are always more beginners than intermediates, which is why there is so much shallow beginner content flooding the market in basically any conceivable topic.
Still, your observation is why Jon Gjengset's "Crust of Rust" series was created:
https://www.youtube.com/playlist?list=PLqbS7AVVErFiWDOAVrPt7...
Crust of Rust is not intended for people who didn't write any programs before, or even for people who've written a bunch of C++ but now are interested in learning Rust (actually those people might be successful with a fairly self-guided approach to get from zero to non-trivial program). Instead it's intended for the people who're beyond beginner but have specific things they don't "get". The first one is "Lifetime annotations" which is exactly the sort of thing that years of experience in BASIC, Javascript and C++ won't help with.